Skillet Lasagna With Spinach and Summer Squash

Step 1

Heat oil in a well-seasoned large cast-iron skillet over medium-low heat. Add onion and cook until softening, 5 minutes. Add the garlic and cook until fragrant, 5 minutes more. Increase the heat to medium, add the zucchini and yellow squash and cook until soft and lightly golden, 10 minutes more, adding the spinach in the last 2 minutes of cooking. Stir constantly until the spinach is wilted. Transfer the cooked vegetables to a plate.

Step 2

While the vegetables cook, crush the tomatoes with a potato masher in a bowl and season with salt and pepper. Spoon a thin layer over the bottom of the pan (about 1/3 of the tomatoes). Add 4 lasagna sheets, breaking off the edges to fit into the curved edges of the pan. Top with half the vegetables, and drop half the ricotta by spoonfuls over the top. Repeat with another 1/3 of the tomatoes, the remaining vegetables and ricotta. Top with another layer of 4 lasagna sheets, the remaining sauce, and layer the Parmesan and mozzarella over the top.

Step 3

Sprinkle with salt and pepper, cover and cook over a low simmer until the pasta is soft and the cheese has completely melted, 5 to 10 minutes. Uncover and continue to cook on medium-high until the tomato has thickened, 5 minutes more. Set aside to cool slightly, 5 to 10 minutes, before cutting. Sprinkle basil and more Parmesan over the lasagna and serve.